A medical catheter defining at least one lumen has been proposed for use with various medical procedures. For example, in some cases, a medical catheter may be used to deliver embolic composition to or within an embolization site in a blood vessel of a patient and/or to deliver another agent or device within a vasculature of a patient. In some cases, a medical catheter may be used to access and treat defects in blood vessels, such as, but not limited to, lesions or occlusions in blood vessels.